Electronically tuned receiver (ETR's) have been proposed which utilize manually actuable switches which cause the receiver to be tuned up or down the band. Digital circuitry responsive to actuation of these switches control electronic tuning circuitry which may include a varactor diode tuner. In general, the digital circuitry includes a reversible counter which counts up or down depending on which switch is actuated. The output of the counter may be converted to an analog voltage to control a varactor in the receiver tuning circuits, or converted to a digital code for insertion in the feedback divider of a frequency synthesizer.
It is an object of the present invention to provide digital control circuitry which is interposed between the tuning circuitry of an electronically tuned receiver and a pair of momentary contact switches to provide three different tuning functions.